GPRSbee and new version of Seeeduino Stalker v3.1

Has someone managed to get the GPRSbee working on the Seeeduino Stalker v3.1? The new version of the Stalker has “some” problems, see but it is unfortunately the platform my beekeeping monitoring runs on.

Code that is running without any problem on the Stalker v3.0 and a GPRSbee is not running on a Stalker v3.1 board. GPRSbee gets a network connection (switching from fast blinking to slow) but after this noting is happening.

In the v3.0 version TX and RX was connected directly with a PCB trace to pin 0 and 1 of the Stalker. In the new version you have an additional IC on board. Is this for switching from hard- to softserial only? I don’t know what kind of IC this is and if it can cause this male-function.

Ok, seems that you have to “power” the module with a switch via D9 first before using it.

pinMode(9, OUTPUT);
digitalWrite(9, HIGH);  

I thought this is not necessary because the LiPo is connected with the GPRSbee directly. But it seems that this IC is switched off by default.

In case someone knows what this IC is … on the right next the bee serial select switch

Hi Clemens
I’m trying to get the GPRSbee (v6) running on my Seeeduino Stalker v3.1. Unfortunatley the LED on the GPRSbee is not blinking a single time. I think I missed soemthing fundamental to power the GPRSbee. D9 is allready set high as described by you above.

I’m trying to get it running with the help of the following script:

Since the newer version of the Stalker (V3.1) has the “Bee Serial Select” switch (set to D5/D6) I changed the Rx/Tx as following:

#define PIN_RX = 5 #define PIN_TX = 6

Do I need to change anything else, or power any pin of the GPRSbee module addiotionaly?
Sorry, I am really a newbie and have only little experience.

Many thanks for any help!!

I think this will not work. A common problem of the SIM800 module is that the power provision is not sufficient! Do not power the GPRSBee via the Stalker’s 3.3V source. You should power the GPRSBee directly with an LiPo and then power the Stalker from the second plug of the GPRSBee, see

Top left red-black cable is the LiPo cable.

Try to use the SODAQ GPRSBee lib: It works for me but I did not use soft serial but hardware serial. So always have a look at your lib what TX/RX pins you are using and adjust it accordingly. On the old Stalker you had to use hardware serial (and soft serial with an additional hardware fix), the new stalker has a mini switch next to the bee socket so double check that this switch selects D0/D1 (hardware serial) or D5/D6 (soft serial) also fitting to your sketch.

I have only tested the hardware serial variant with the SODAQ lib and the Stalker 3.1!

It is also a good idea to de-activate the pin on the sim card. At least first to get it initially running.

Hi Clemens
Many thanks for your reply.
Ok, I will try it with your suggested power-supply solution and have a look on the SODAQ library. Hope I get it running as well :smile:

Thank you. I also try to use GPRSbee with stalker v3.1 without success. I tried to used uarts bee with GPRSbee and connect uarts to stalker. With this configuration it works, but it’s not realy a good solution. On your picture, I can see a Stalker v3 not a v3.1. Do you have a code sample for the v3.1. My problem is that I don’t have any power on the GPRSbee.
Best regards,

Hi Gert, yes, I have a code version for the Stalker 3.1! I did just some initial tests so it is not bullet proof. Problem is the 3.3 V power rail. It’s not working with 2x DHTxx and 1x DS18B20 so I used the power switching pin D9 as power source also instead of using 3.3 V (!!) see also[FAQ]bio%20asked%20about%20Seeeduino%20Stalker%20V3.1-t-11576.html

I tried to attache my code but the forum software says file mformt *.ino not supported and while including the code in this post “Body is limited to 32000 characters; you entered 36379.”

If you use Github, you can link to the repository in the forum here. It will show a preview of the code with the ability to link through to the rest.